The wind tunnel fan

The fan in the Braunschweig Low-Speed Wind Tunnel (NWB) is 4.7 metres across. With a top speed of 320 kilometres per hour, the tunnel is classed as a 'low-speed' wind tunnel. The Braunschweig Low-Speed Wind Tunnel (Niedergeschwindigkeits-Windkanal Braunschweig; NWB) is limited to this top speed since aircraft are not subjected to higher speeds than this during take-off and landing, nor are cars during highway travel. Higher-speed tests are performed in 'trans-sonic' wind tunnels.